Help needed Jacobs Extarder

We have the Jacobs Extarder on our coach and can never seem to know if its working or not.
What gear do these things usually kick in at?
Our coach is a 1993 Pace Arrow Vision Turbo Diesel with the C8.3 engine.
Dont tell me to read the manual. It says less than nothing.
I flip the switch on and never feel anything different. The regular brakes have been checked and they are supposedly in fine condition.
At least thats what Freightliner said. I dont feel confident with them and would like to know about using the Jake.
Can someone shed some light?

With an electronic engine the Extarder will activate when the ECM senses zero fuel flow.  The ECM will also preselect a low gear on the transmission (usually 2nd but some have reprogrammed to 4th).  It will also disengage the cruise control.  As long as there is positive fuel flow, the Extarder won't engage.  With it on, when going down hill and your foot off the accelerator, it should engage and you should feel the effect.

I'm not sure just how it works with a non-electronic engine, but I would expect similar behaviour.  It is possible that the valve mechanism has corroded and isn't activating.  I would take it to a Freightliner Oasis service center if you think it may not be working correctly.

I hate to be the bearer of possible bad news but it could very well be that your Jacobs Extarder exhaust brake is not working if it was not maintained properly over the years. ?Exhaust brakes require lubrication with a high temperature synthetic lubricant such as Super Lube. in Failure to lubricate properly results in the shaft becoming frozen and/the actuator becoming frozen into usually the open position. ?Infrequent use can also have a negative effect on exhaust brakes. ?

Operation or non-operation of the exhaust brake can be confirmed by having somebody drive the coach and engage the exhaust brake while observing the exhaust brake. ?The exhaust brake is located in the exhaust stream just prior to the turbo. ?
I would recommend taking the coach to a cummins shop for check and repair/replacement.

Ron, I found this hard to believe at the tme, but I had previously taken the coach to Cummins Atlantic in Greensboro, NC. The highly touted "Coach Care Specialists" people said they had never heard of an extarder brake. I reminded them of the fact that they were a Cummins DEALER and they said an "extarder isnt a Cummins unit." At that point in time, I gave up. I will call the Freightliner people like Ned suggested and see if they can help.
Thanks to both of you.

Hi Dianne,

Just found this after responding to another message from you.

The Jake Extarder is an exhaust brake. Exhaust brakes work better with the smaller engines. I have one on my ISC and it does not do much in retarding unless the rpms are high. I complained about it to a Spartan rep. He said nobody will admit it but Cummins apparently had problems with burnt valves and made Pacbrake put holes in the butterfly to reduce the back pressure. I would assume they might have done the same with Jake Extarders. I have not removed mine to see if that is true. I have driven Bounders with the smaller engines and the brake works much better than mine.

Dianne,

The Extarder isn't made by Cummins, is a Jacobs product and is put on by the coach manufacturer.  It's just one model of exhaust and engine brakes made by Jacobs.  Still, it's surprising that a Cummins shop wasn't familiar with it.

Hi Jim, and thanks for your reply.

All I know is what the sticker says in the cockpit. It says "Jacobs Extarder."

I have read the manual and all it says is to cut it on and not to accelerate when it is on. Does this mean that they intend for you to keep throwing a switch every time you want it to work?

I am a woman of fairly reasonable intellect, but the so called instruction manual baffles me and IMHO is pretty useless in terms of practical operational instruction.

I am left wondering what I DO have here. Is it an engine compression brake or an exhaust brake?

Will the "REAL" Jake Brake please stand up???

Ned,

Thanks for your replies.

Yes, even tho it is made by Jacobs, I just thought that a Cummins dealer ought to know about anything hooked to or affecting their engines.

Dummy me. I learned the hard way. But then again, when I was handed an $881.00 bill that day for an oil and filter change, I should have learned that Cummins Atlantic isn't on my side to begin with. I quickly sat down with the Cummins engine manual and typed out
the steps to an oil and filter change on my coach, and while I read the steps out loud and provided moral support, Gil was able to change the oil. Have all of you who are probably getting a good laugh by now figured out that this is our first pusher?

dpickard said:

Have all of you who are probably getting a good laugh by now figured out that this is our first pusher?

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Dianne, I doubt anyone is laughing as many of us learned the hard way. You were smart enough to ask for help before learning any more stuff the hard way.

From your description, it sounds like your Extarder is manually operated and not connected to the engine computer (you probably have a mechanical engine, no ECM).  Follow the instructions, turn it on when needed, and turn it off when you have your foot on the accelerator.  You don't need it for most situations, but when coming down a steep grade, you'll be glad you have it as a diesel engine offers NO braking at all, unlike a gas engine.  The procedure for descending a grade is to use the same gear on the transmission as you use going up and keep your speed down so the transmission doesn't upshift.  Turn on the Extarder, downshift the transmission and get the speed down before starting down the grade.  When you get to the bottom, turn the Extarder off and drive as normal.

Ned,

THANK YOU!

Being a dog show person and having driven gas coaches for years, I have long drooled over the 40 and 45 foot pushers who went whizzing by me going up a mountain and wondered what the difference is. Last year I went on a mission. I searched high and low for an "affordable" (HA)  pusher in great shape, and after 5 months of searching and praying hard that I wouldnt get ripped off like I did on all 6 of my gas coaches over the years, I came up with the one we now own. It has been an absolute DIAMOND!!! For a used, mid level pusher, it is solid as a rock. I was thoroughly impressed with it overall, and during the past year, in 12,000 miles of all kinds of terrain, it hasnt missed a beat. I bought it off ebay and the former owner drove it from Mesa, AZ to Houston to meet me. I flew out to Houston from Greensboro, NC and drove it back alone because Gil had to hold down the fort here and work. The only time I have ever been SCARED driving it is when I am going thru mountainous terrain like I am going to do tomorrow as I embark on a trip from Reidsville, NC to Springfield, IL. I just dont feel confident with the regular brakes alone; even tho I have had the coach gone over and no one could find one THING wrong with it.
Everyone should be lucky enough to find a used coach that has been maintained like this one. The former owner kept records of practically every time he turned a screw on it. Unfortunately, he passed away, so I cant ask him how to work the Jake.

Thanks again for your assistance.

I am afraid I would have lost all confidence in that Cummins shop if they told me they had never heard of an extarder brake. The Jacops Extarder Brake is an exhaust brake and as I recall was at one time recommended by Cummins. ?Think if it was me I would be contacting Cummins home office to let them know of my dissatisfaction with that particular shop.

As Jim indicated an exhaust brake is more efficient at higher RPMs. ?On our coach when the exhaust brake is engaged the transmission select a lower gear. ?Some rigs the lower gear will be 2nd others 4th. ?When the coach speed is slow enough for the transmission to shift to a lower gear it will do so. ?Just because a lower gear is selected doesn't mean it has shifted to that gear. ?The transmission is designed to protect the engine from over speed and should not actually downshift to a gear that will cause the engine to overspeed.

Drive your coach at 40 MPH let up on the accelerator and then select 4th gear, then engage the exhaust brake. ?If it is working you will feel the coach slow down when the brake is engaged. ?Usually a an exhaust brake is set up so that it will not operate except when the accelerator has been released.

Hi Dianne,

As others have mentioned you definitely have an exhaust brake and Cummins should have known all about it. Secondly, I would seriously question that $800 bill. No oil change should ever cost that much. I've had both the engine and transmission serviced and together they weren't near that cost!!

dpickard said:

We have the Jacobs Extarder on our coach and can never seem to know if its working or not.
What gear do these things usually kick in at?
Our coach is a 1993 Pace Arrow Vision Turbo Diesel with the C8.3 engine.
Dont tell me to read the manual. It says less than nothing.
I flip the switch on and never feel anything different. The regular brakes have been checked and they are supposedly in fine condition.
At least thats what Freightliner said. I dont feel confident with them and would like to know about using the Jake.
Can someone shed some light?

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I've had one job done by Cummins Atlantic (in January 2004), I had gaskets changed on the oil pan, rocker arm cover, and had them change oil rather than re-use old oil as is the std approach. The bill for this extensive work was $107.26 for parts and $341.90 for labor. Therefore, it doesn't seem possible that a simple oil change was $800. Either they did more or the bill is in error.
I suggest you contact the President of Cummins Atlantic who is Michael Grace. His e-mail is [email protected]
I have know his family since the 1960's when his father worked with me at Cummins (before buying this distriubutorship in the late 1960's) and? Mike was a teenager They have nearly 40 years under thier combined leadership and I'm sure will either explain the bill and/or correct it if wrong.? Your engine from your date and description is a mechanical one.?

I think the problem/confusion about the Jacobs Extarder is simply one of usage. Generally speaking, mechanics and indeed most engine people will talk about exhaust brake or engine brake or to make matters worse -just a Jake brake. The word extarder was adopted by Jcobs but never really became common usage.  I strongly suspect that if you'd said exhaust brake ; the answer would have been markedly different. BTW- for those with newer engines the issue has become more complex as Jacobs is now producing a brake for Cummins and designed by Cummins called a C Brake and I see it wrongly referred to on this site and others as a Jake Brake.

Blueblood,

Are you a friend of the owner(s) of Cummins Atlantic? That was a pretty glowing endorsement. Perhaps you received a discounted bill?

Unfortunately, my experiences there have not been so happy. For example...

1. The day I had the oil and filters changed, I told them I heard a belt squealing. Not only did they tell me they didnt hear anything, they went as far as to say that the belt was in great shape and needed nothing. Not even an adjustment...
On the drive home to Reidsville, the belt broke in the middle of Highway 29 and I had to wrestle my dead 25000 pound coach to the curb with no power steering.   

2. On another occasion, thinking I had water in the fuel, I happened to let too much fuel out of the filter at the rear of the coach and got air in the line. I was charged $285.00 for a tech to come to my home and do nothing more than spray a shot of starter fluid in the air filter.

3. I was also told by them that my diesel genset needed a water pump. It was not leaking and had no symptoms. I had it rechecked by another Cummins dealer and they checked the generator and then proceeded to dounle over in laughter. The generator has never had any issues since I became owner.

I think these issues speak volumes. 

dpickard said:

Blueblood,

Are you a friend of the owner(s) of Cummins Atlantic? That was a pretty glowing endorsement. Perhaps you received a discounted bill?

Unfortunately, my experiences there have not been so happy. For example...

1. The day I had the oil and filters changed, I told them I heard a belt squealing. Not only did they tell me they didnt hear anything, they went as far as to say that the belt was in great shape and needed nothing. Not even an adjustment...
On the drive home to Reidsville, the belt broke in the middle of Highway 29 and I had to wrestle my dead 25000 pound coach to the curb with no power steering.? ?

2. On another occasion, thinking I had water in the fuel, I happened to let too much fuel out of the filter at the rear of the coach and got air in the line. I was charged $285.00 for a tech to come to my home and do nothing more than spray a shot of starter fluid in the air filter.

3. I was also told by them that my diesel genset needed a water pump. It was not leaking and had no symptoms. I had it rechecked by another Cummins dealer and they checked the generator and then proceeded to dounle over in laughter. The generator has never had any issues since I became owner.

I think these issues speak volumes.?

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No, I don't receive discounts.

I don't kown about all your problems but they sound very odd indeed. I'll refer owner to this discussion and let him read them for himself if he so desires. I'll back out from any further involvement.?

Dianne,

One thing I have learned in owning a diesel pusher.... NEVER EVER fool with the water/fuel separator!!!!!! When I have the oil changed I also have them change the oil/fuel separator along with the standard fuel filter. Never had a problem since.

LOL....Jim,

ANOTHER lesson learned the hard way for me. This wonderful coach has really suffered at my hand. Perhaps it will survive my ownership and the local Cummins dealer yet!

Trying to be a diligent owner has obviously gotten me into a jam or two.

There I was, standing with the Cummins manual in one hand, looking the engine over, trying to figure out what the various filters were.
Wait...do I see water in that litttle clear plastic bowl thingy??? It says here that should be drained daily. I'll just let a little out to be safe...Oops!

Dianne,

I, too, learned the hard way. ;D

dpickard said:

LOL.... and the local Cummins dealer yet!

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For FWIW and clarification - Cummins Atlantic is not a Cummins dealer. They are an independent company serving as a Cummins distributor who in turn create Cummins dealers.  This distinction is important in several respects. Distributors generally possess more resources e.g. direct lines of communication to Cummins, technical staffs, training facilites, etc than dealers and in describing a problem to Cummins Powermaster (1-800-DIESELS) or in writing to them saying a dealer vs distributor may fail to elicit proper understanding of whom you were dealing with.